Tuning Box: Does it Affect Fuel Consumption?

Hello,

I'm currently pondering the following question.
I'm currently driving my Golf 4 TDI ALH with a tuning box.
Since the tuning box essentially only modifies the values related to the amount of diesel injected by the fuel injection pump, I wonder if the readings on the multifunction display regarding fuel consumption are still accurate, or does the computer calculate the fuel consumption based precisely on that value from the fuel injection pump?

I already thank you .

Thorsten.

Hi totto2k.

The displayed MFA values are no longer accurate for this type of tuning.
The values recorded in the vehicle's onboard computer are used to calculate the diesel consumption.

'Thank you!'

I already suspected that... let's see what the actual fuel consumption says when I fill up the tank next time .

Thorsten.

'On my Golf 4 with a 74kW ATD engine, the FIS (fahrzeugintegrierter Speicher - integrated vehicle computer) used to...'
(with this cheap, 5-cent diesel temperature modification 'tuning').
Approximately 10-15% too low.
Without 'tuning,' it's about 5% too high.

With my KW-Systems gauge, the consumption values matched the FIS almost 100%, perhaps because it barely consumed any more than without it?

Best regards,

Okay, here I am again:

'In the last 'leg' (haha!), I averaged 7.0 liters per 100 kilometers. The onboard computer (FIS) told me 6.0 liters. That's a difference of 16%. This also means that, on average, it's injecting 16% more fuel, which suggests 'there's still room for improvement!''


Thorsten.